JoeCreates
commented
8 years ago Is this basically a combination of previous related issues? If so should we close those?
I'd like to make some additions. First, it would be nice if updating the hitbox after scaling didn't simply remove any modifications to offsets you'd made, but also scaled those. Something to add to the considerations is the nape stuff. FlxNapeSprite presently uses origin and is incredibly trick to use when scaling sprites.
Rethinking the position/rotation/collision/rendering points
This is a draft! Not relevant for now
Position problems - Origin problems -
positionand theoriginof a sprite are two different things: thepositiondetermines the top left corner of a sprite's frame and theoriginis the point around of which a sprite's frame should rotate/scale.Since this is such a wide subject, affecting every major aspect of the framework, I feel like this should get its own issue. I've round up all the info I can find for reference:
Stuff to consider
Scale, Zoom, Offset, Scroll(Factor), Size, Frame, Hitbox, Angle, Velocity, Acceleration, Drag,
The current implementation
Position
definition in HaxeFlixel:
A point, measured by pixels, that sets the sprite's frame's location in the game's window.
Origin
definition in HaxeFlixel:
*A point for the sprite to rotate and scale around. The default point is the center of the sprite's graphic frame.
Right now It is used to find "the center of the sprite" (whatever that means, couldn't be more vague)
Zoom
definition in HaxeFlixel:
.
Frame / Graphic / Bitmap (frameWidth, frameHeight)
definition in HaxeFlixel:
.
FlxAtlas
definition in HaxeFlixel:
.
Size (width, height)
definition in HaxeFlixel:
The size of the sprite's
graphic. When changed the sprite usesscaleto make it (physically) bigger, but does not update the sprite's hitbox accordingly.Scale
definition in HaxeFlixel:
.
Hitbox / Game object / Bounding box
definition in HaxeFlixel:
.
Offset /
definition in HaxeFlixel:
.
Optimizations/Fixes:
originis misleading: Unlike what the name's suggesting, this is actually apivotpoint ! !!!.*size/scaledoesn't change the hitbox's size unless you call updateHitbox (Why?!).origincan change the sprite's positionSuggestions
Registration point
https://youtu.be/efUsAANqsEk?t=6m45s - A point from (0,0) to (n,n) that determines the z-order of objects on screen like so: When an object has a bigger (, y) point it's rendered on top of the smaller (, y).